In 12-inch nonstick skillet, cook ground turkey and onion over medium heat about 8 minutes, stirring occasionally, until turkey is no longer pink; drain.
Stir in water, tomatoes, peas and contents of seasoning packet from soup mix. Break up noodles; stir into turkey mixture. Heat to boiling, stirring occasionally. Reduce heat; cover and simmer about 6 minutes, stirring occasionally to separate noodles, until noodles are tender.